I contacted Smith & Wesson about getting part numbers in an exploded view to make ordering parts easier and this is there response:

We do not distribute exploded views any longer, sorry. The M&P 15-22 format is new and the engineers are constantly trying to improve the format whether it is a design or user issue, so they will not allow us to send out bolt related or extractor related parts. When the guns are returned for repair they are examined (research the failure) and updated to the latest format. I hope this answer your question. We have technical specialist that you can call at anytime. I will give you one specialist in particular:
Paul Gazda 800 331 0852 EXT 4125 he will be able to converse in the greatest of detail with you on the design and function

Well I guess that is it. Nothing that touches the bolt or extractor is user serviceable, bummer.

That's disappointing. In the past it was mentioned that you could actually buy a replacement bolt...I wonder if the entire bolt assembly is still availalble, or if it's just the individual parts that aren't? Sure would be nice if someone would replicate the ejector.

They will sell you parts all day long, as long as you have the PN's.. That's the rub.. This is what we have so far!

I thought we did know the ejector part number and they still wouldn't sell it.

Yeah, I gave him the part number. No go.

I didn't know the part number of the breech sleeve... or whatever it is called though.

That seems to be the one exception, and I have no clue as to why. Every other part has been purchased by forum members.

No one knows the breech sleeve number yet, huh?

Sadly no! wish I could help with that one! Do you have the PN for the barrel? I may do an updated diagram

IMO, I will wait till much later to try to grapple with all-most, better improvements for my firearms trigger assembly.

I'm confused? The Fire Control Group of the 15-22 is standard AR affair.. You can order any trigger parts your heart desires.

The upper is only $20? If that's right, I'm definitely going to get T22's modified handguard converter nut and I won't feel bad about taking a Dremel to the upper.

Yes that is correct I have a replacement upper sitting here that I bought from them.

I only have the part number for the threaded barrel. I got it off another thread. I was able to order it. It doesn't have the breech sleeve attached to it.

S&w405020000 b106 22 AR bbl threaded 16.5" rev A

Okay I will add it to the list and annotate that it does not come with the chamber block, ejector or roll pins. Will upload photo shortly.